Speech valves of the type specified above are known in a variety of forms, and connect two substantial properties in a single device, specifically, on one hand, they provide moisture in the air that is breathed, and on the other hand, they enable a person having undergone a laryngectomy or tracheotomy to speak, in transitioning from an open position into a closure position.
With surgical interventions in the upper respiratory tract, the insertion of an artificial breathing hole (tracheostoma) in the trachea may be necessary, in order that air may be inhaled directly into the lungs, bypassing the oral cavity and larynx. With persons having undergone a laryngectomy or tracheotomy, filter systems are normally used, which are composed of an adhesive bandage having a filter inserted therein, normally made of a self-adhesive base plate, or a tracheal cannula—normally made of plastic—in which filters of different types can be inserted. The filter systems, which are used in laryngotracheal items, such as tracheal cannulas and bandages or base plates, include the so-called moisture and heat exchangers, also called artificial noses. These serve to reproduce missing regulation mechanisms for heating and moistening the breathing air for persons having undergone a tracheotomy, or a laryngectomy, and to prevent the trachea from coming in contact with dry, cold and unfiltered air. This is because mucous production increases with the irritation caused thereby, accompanied by the danger of clogging as a consequence. The inhaled air is moistened, heated and simultaneously filtered by the moisture and heat exchanger. As a result, the aforementioned clogging is substantially prevented. Wearing the artificial nose on a regular basis helps thereby, particularly with secretion, because, by moistening the mucous membranes in the trachea, secretion is reduced. Moisture and heat exchangers can also be equipped with a speech function, and are then referred to, as also set forth for the present invention, as speech valves, wherein, however, other terms, such as voice valve, are also popular.
DE 699 20 440 T2 discloses a generic device, referred to therein as a voice valve with a filter, wherein the voice valve serves as the connection to a tracheostoma, and has a regenerative filter for moisture and heat exchange during breathing through the voice valve, as well as a housing, which receives the filter, and a first opening on a filter side, for connecting to the tracheostoma, and at least one second opening on a side lying opposite the filter, connecting to the environment, and a manually operable valve element for blocking the passage of air through the filter, wherein a sleeve extends into the interior of the housing, and forms a valve seat, which defines the first opening, in order to engage with the valve element in a sealing manner, through a manual actuation thereof.
All of the devices disclosed in DE 699 20 440 T2 require that, with a closure of the proximal opening, the filter is at least partially compressed. Due to the elasticity of the filter material, the voice valve disclosed therein then transitions from the closure position to an open position. The disadvantage with this, in particular, is that on one hand, the filter material becomes fatigued through the compression and decompression during the transitions into the closure position and the open position of the voice valve, and on the other hand, the elastic property of the filter material weakens through use, such that a secure opening and closing is no longer obtained.